Propeller



A. ASSALA PROPELLER Filed June 25, 1922 Nov. 4-. 1924.

Patented Nov, 4, 1924. i

UNITED STATES PATENT, oFF cE.

ANTHONY ASSALA, or as Memes, IOWA.

rRorELLEn. 5

Application filed m 23,1 1922. seri l No, 570,424.,

The object of my invention is to provide' a propellerwith increased efficiency and durability for use in connection with aero- I planes or the like.

, -My invention consists in the construction ofthe propeller and the arrangement and combination of the propeller-blades, the hub and its shaft connections, whereby the .objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claims, and illustrated in the accompanying drawings,in which: o o Figure 1 shows a side elcvationof a propeller embodying my invention.

Figure 2 shows a rear elevation of the same. I I

Figure 3 showsa detail, sectional view on the line 33 of Figure 2. r Figure 4 shows a side elevation of my improved propeller, a portion of whichis in section on the line H of Figure 2. v

Figure 5 shows a detail, sectional View on the line 55 of Figure 2; and

Figure 6 shows a sectional viewion the, I I, p

relatlveto the, hub, attention is called to I line 66 of Figure 4:. i 7

Referring to the accompanying drawings I have used the reference numeral 10% indicate a' propeller shaft of ordinary construction. This shaft is fitted into a hollow hub which comprises a substantially cylindrical body portion 11, the dimensionsat the front thereof being slightly greater than the dimensions at the rear. The front end is open and internally screw threaded at 12.

The cap or front end of the hub is 'indi cated by the numeral 13 and screws into the screw threaded portion of the front of the hub body. This cap is rounded and/tapered from its rear to itsfront and along lines.

that will offer the least resistance to its advance through the air. v

At the rear of the hub is a flange 14 keyed or otherwise secured to the shaft 10 and riveted or otherwise permanently connected to the rear of the hub.

Near the front of the hub there is a flange 15 keyed or otherwise secured to the shaft, and riveted or otherwise permanently connected to the hub, thus detachably fixing the Sil ia within the liuban d fimh brlacitg the hub relative toithe shaft.

'impioved propeller and eachis connected with and secured to the :hubby, means of two flanges 16. and 17,,spaced; apart: from I Thereare preferably two 'bladesionlmy i each other andpreferabIy formed integral with. ub and extended laterally. ouowardly therefrom.

he blades, which are preferably made of wood, areindicated generally ,by the refer ence numeral 18, and are. inserted between. theflanges 16 andli and permanently connected therewithbyrivets or thelike. r

kt, .the outer edge of'each blade prefer ablyyprovide a, metal. binding member .19

permanently connected with the blade by rivets or the like.

It is the shape of the blades andtheiriar rangem'e'nt or angularity with: relation to the hub Iat'various points which comprises an essential and important feature of ,my inyention', As viewed from the rear, as shown in Figure2,theforward edge of the blade is indicatedby the reference symbol: A and the rear edge by the reference symbol B. The rcontourof the, outer edge of the blade formswits front edge, and itsrear is of gradually increasing diameter with respect to. the center of the hub.

theblade In .regard to} the angularit-y of Figure 5,,which is taken. oirda section line from the centerof the hub radially. through the advanceedge portion of the blade, and in this view it will be seen that this part of the bladeinclines outwardly and forwardly relative to the line of advance of; the pros pellerr i w f Nearthe central portionnof theblade, as shown in Figure 4;, the blade is substantially at, right angles to the driving shaft and at the rear edge 0f the blade,.as,shown in Figure 3, the blade inclines outwardly and rearwardly relative to the lineof advanceof the propeller. ,In additionto. this the rearouter portion of"the blade is curved, as shown at C in Figure3, ina directionrearwardly to the lineof advance iofthe propeller By means of thefeatures of shape and ployed in .an aeroplane and is traveling through the air, the relative particules'oi' air, but as soon as any particules of air are engaged by. the rapidly revolving propeller,

they will commence to move in the direction in which it is beingforced by thepropeller blades.

When, for instance the advance edge of" amount of efficiency s lost because of the the propeller has progressed through the stillair as far as. say for instance, toward -theline '5 of Figure 2, then the previous stillair that is thusengaged will be moved 'rearwardly and by centrifugal action will have a tendency to throw it outwardly from thehub. c Howeveiy as the blade farther progresses in its revolution, it will reach farther out into the still air, and beforethis outer circle,

asitmight be called, of still air hasbeen engaged by the propeller blade and, started to move rearwardly and outwardly, the outer circle of still airwill oppose the travel I of the inner circle of still air in; a direction a outwardly. Y

In other 'words, the outer circumference of still air is eventually engaged andmoved by the blades, and so engaged andjmoved until after it has served the purpose of I forming a cushion to prevent the inner circles of still air that were firstengaged by the blades from sliding outwardly in a radial direction relativeto the hub.

In addition to this the rear-edge B of the propeller blade at its outer end is'inclined rearwardly, and this, as will be seen, tends to hold the air that is being impinged'by, the blade against an outward or radial movement, or in other words, this curvature at the rear of the-blade tends tofurther compress the air that has been engaged by the blades and pushed'rearwardly andoutwardly. i i

Furthermore, by having the-front edge of the propeller blade inclined outwardly and forwardly relative to a line at right angles to the'shaft, and-the rear end of the pro pellerblade inclined outwardly and rearwardly; relative to a line at right angles to the shaft,

the following advantage is gained:'-

"By having the front edge of the blade inclined forwardly, a relatively larger amount of still air is reached or engagedby v the blade than by having-the rear of the propeller blade inclined rearwardly. This air is u niformly compressed or pushed upon'by which are shaped spirally like a SIIGW, and

in blades of said class a line drawn from the axis radially at any pointwould show the blade to be arrangedat right angles to the axis, and with such blades a considerable ward direction with relation to the blade,

whereas with my improved form of the blades, this tendency isopposed in two ways: I First, by reason of the fact that the blade increases in diameter as it progresses through its effective stroke, and hence the air that is started to move outwardly and rearwardly' by the advance portion of the blade iscushioned or retarded in such movement by the still air that is later engaged by the outer portions of the blade; and also the efficiency of action of my improved blade upon the air is increased'by having the front edge inclined forwardly and its rear edge inclined rearwardly.

I claim as my invention:

1. An improved propeller comprising a cylindrical hub a hub cap detachably secured to the front of'the hub and shaped to offer a minimum resistance to, theair, two flanges within the hub, a shaft detachably mounted in said fianges,isaid hub being also provided with two flanges for each blade extended outwardly therefrom and spaced apart, a propeller blade inserted between said flanges and extended outwardly'from thehub and firmly secured between the flanges. I Y

2, An improved propeller comprising a cylindrical hub, a hub cap detachably secured to the front of the hub and shaped to ofler a minimum'resistance to the air, two flanges withinthe .hub, a shaft detachably mounted in said flanges, said hub being also provided with two "flanges for each blade extendedoutwardly therefrom and spaced apart, a propeller blade inserted between said flanges and extended outwardly from the hub and firmly secured between the flanges, and a metal binder at the outer edge of the propeller blade, for the purposes stated. v

Des Moines, Iowa, June 15, 1922.

ANTHONY ssam. 

